Related Experiment Video
Updated: Jun 23, 2026

14:23
A Restriction Enzyme Based Cloning Method to Assess the In vitro Replication Capacity of HIV-1 Subtype C Gag-MJ4 Chimeric Viruses
Published on: August 31, 2014
Resistance and viral subtypes: how important are the differences and why do they occur?
1McGill AIDS Centre, Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2. bluma.brenner@mcgill.ca
Current Opinion in HIV and AIDS
|April 18, 2009
Summary
Antiretroviral therapy is effective for non-B subtype HIV-1 infections, showing comparable drug resistance profiles to subtype B. Understanding subtype differences is crucial for optimizing treatment and prevention strategies globally.
Area of Science:
- Virology
- Infectious Diseases
- Drug Resistance
Background:
- The global HIV-1 pandemic comprises 11 subtypes and 34 recombinant forms.
- Knowledge of antiretroviral drug response and resistance is primarily based on subtype B, prevalent in Europe and North America.
- Non-B subtypes account for approximately 90% of worldwide HIV-1 epidemics, yet comparative data is limited.
Purpose of the Study:
- To review recent publications on intersubtype differences in HIV-1 susceptibility to antiretroviral drugs.
- To examine emergent drug resistance patterns in non-B HIV-1 subtypes.
- To highlight the implications of HIV-1 subtype on treatment and resistance.
Main Methods:
- Literature review of publications from the past year.
- Analysis of clinical studies on antiretroviral therapy outcomes.
- Comparison of drug resistance profiles between HIV-1 subtypes.
Main Results:
- Antiretroviral therapy is beneficial for non-B subtype HIV-1 infections, with resistance profiles similar to subtype B.
- A 10-15% sequence diversity in the Pol region influences viral response to various antiretroviral drugs.
- Specific non-B subtypes exhibit distinct signature mutations and resistance pathways.
Conclusions:
- Understanding intersubtype differences in drug resistance is vital for effective HIV-1 treatment strategies, especially in resource-poor settings.
- This knowledge can aid in developing prophylactic approaches to prevent HIV-1 transmission.
- Optimizing treatment and prevention requires considering the specific HIV-1 subtype.
Related Concept Videos
Viral Mutations
A mutation is a change in the sequence of bases of DNA or RNA in a genome. Some mutations occur during replication of the genome due to errors made by the polymerase enzymes that replicate DNA or RNA. Unlike DNA polymerase, RNA polymerase is prone to errors because it is not capable of “proofreading” its work. Viruses with RNA-based genomes, like HIV, therefore accrue mutations faster than viruses with DNA-based genomes. Because mutation and recombination provide the raw material for adaptive...
Size and Structure of Viral Genomes
Viral genomes exhibit remarkable diversity in size, structure, and composition, influencing their replication strategies and interactions with host cells. These genomes consist of either DNA or RNA and may be linear or circular. Additionally, they can be single-stranded or double-stranded, with each configuration affecting how the virus propagates within a host. RNA viruses, for instance, generally have smaller genomes than DNA viruses, a factor that contributes to their high mutation rates and...
Viruses with RNA Genomes
RNA viruses are categorized into positive-strand, negative-strand, or double-stranded groups based on their genomic structure and replication mechanisms. This classification dictates how they exploit host cellular machinery for protein synthesis and replication. Some RNA viruses also utilize reverse transcription as part of their life cycle, further diversifying their replication strategies.Positive-Strand RNA VirusesPositive-strand RNA viruses have genomes that function directly as messenger...
Introduction to Virus
Viruses are unique biological entities that blur the boundary between living and non-living systems. Although they lack cellular structure and metabolic processes, they can exhibit characteristics of life when infecting a host. Their defining feature is a nucleic acid core, composed of either DNA or RNA, encapsulated within a protein coat called a capsid. This simple structure allows them to invade host cells and use their machinery for replication efficiently.Viral Structure and...
Viral Structure
Viruses are extraordinarily diverse in shape and size, but they all have several structural features in common. All viruses have a core that contains a DNA- or RNA-based genome. The core is surrounded by a protective coat of proteins called the capsid. The capsid is composed of subunits called capsomeres. The capsid and genome-containing core are together known as the nucleocapsid.
Viral Recombination
Cells are sometimes infected by more than one virus at once. When two viruses disassemble to expose their genomes for replication in the same cell, similar regions of their genomes can pair together and exchange sequences in a process called recombination. Alternatively, viruses with segmented genomes can swap segments in a process called reassortment.

